1. Field of the Invention
The present invention relates to an electronic basic unit or a functional module for use in a system on chip. The invention also relates to an exposure-mask arrangement for photolithographically producing the inventive electronic basic unit, to a system on chip comprising inventive electronic basic units and to a corresponding production method.
2. Description of the Related Art
A system on chip (SoC) refers to when complete systems comprising microprocessors, memories, communication interfaces and/or digital and analogue circuit parts, for example, are integrated on a single semiconductor chip. SoCs then meet the demands on reliability, dimensions and low energy requirement at a high processing speed and a relatively low price. The large-scale integration of such circuits on a single semiconductor substrate by combining all the system components on one chip results in the fields of use for such an SoC being restricted, however. This is because it is possible to use only the ones which are produced as a system function by the SoC development.
To provide flexible and user-adaptable solutions, what are known as ASICs (Application Specific Integrated Circuits) were developed. Gate arrays, for example, contain regular arrangements of digital basic elements which can be manufactured in advance in large quantities as “masters”. Connections between the cells or the wiring for the integrated circuit can then be programmed in the production process using masks, for example. The masks are then produced for the last technologically required planes and the preparation of the circuit is thus finished. The relatively high level of flexibility in the field of application of such gate arrays is bought at the cost of a high area requirement and power consumption, however.
In addition, what are known as “field-programmable gate arrays” (FPGAs) are known which are fully programmable by the user. In order to be appropriate for a large number of instances of use and system requirements, these need to have a large number of universal structures comprising gates and logic elements. This means that although FPGAs can be used flexibly they have an even higher area requirement than mask-programmable gate arrays and a high energy requirement. FPGAs are particularly suitable for very small quantities, where it is not economical to integrate the system function on a chip fully.
On the other hand, fully integrated SoCs cannot be modified once mask production has ended. If changes are to be made to an existing design for an SoC, then although the design phase allows the use of macros for electronic basic units in the SoC in a description language or in a form of checked layout data again it is necessary to carry out full mask production for the photolithographic process again. Particularly the production of such mask sets is very expensive.